return to previous lines

Question

how to return to previous lines in a program?(do again some lines!)

Answer 1

That is where you should use a function.
Write the lines in a function and call the function as many times as you need it.
example:

def f(x,y):
print("I am reusing these lines")
print(x*y)
print(x+y)
print(x**y)

f(2,3)
f(3,4)